AF with the Canon 600 II

I've noticed some surprising AF behavior with my 600 II.  When using the 1D4 on the 600 II, the AF hunt speed is much slower than on either the 500 I or the 800.  In contrast, the 1DX AF hunt speed is much faster on the 600 II than on the 500 I or the 800 (at least, when using a TC).  The table below shows the time, in seconds, required for a given lens/TC/body combination prefocused at the MFD to AF on an object at 150m.  I timed these with a stopwatch to the nearest 0.1 s. 
These results are quite surprising to me.  I did not expect my 1D4 to have slower AF performance on the 600 II than on the 500 I or 800.  Would be curious to know if anyone else has observed this.

FWIW, I also did the tests with the 1D3 and 1Ds3, and got exactly the same result as the 1D4 in every test.  Also, I am aware that an AF-related firmware update was required for some 600 II copies, but I confirmed that the serial number of my 600 II is not included among those that require the update.

I also did a similar test in which the AF ran between infinity and 6.5 meters, which may be a fairer comparison, given the differences between MFD for the lenses.  The results are qualitatively the same, but I included them below in case anyone is curious.

So,

1. Are they supposed to be the same...should they be the same?
2. Do your photographs look better or worse because of the difference in AF speeds?

Hi Jacob,

That is an amazing performance for the 1Dx/600 combo with coverters! Essentially, there is no penalty in performance and is as fast as any of your other lenses. Do you have a 300/2.8 to test? I would be curious to see if the 300/2.8 + 2x can focus (accurately) as the native 600.

Cheers,

Jim

hullyjr wrote:Hi Jacob,

That is an amazing performance for the 1Dx/600 combo with coverters! Essentially, there is no penalty in performance and is as fast as any of your other lenses. Do you have a 300/2.8 to test? I would be curious to see if the 300/2.8 + 2x can focus (accurately) as the native 600.

Cheers,

Jim

I have the 300/2.8 IS I, but didn't include it in the original tests.  I pulled it out just now and did a quick test with the 1DX, with and without a 2x.  The AF hunting is much slower with the 2x.  So it looks like it behaves like the other version I superteles, as one would expect.  I would guess that the version II 300 (and probably also the 400 and 500) would behave like the 600 II, but I don't have any of those lenses to test.

I should stress that I am only testing AF hunt speed. There are a lot of other aspects of AF behavior that affect performance, but they are not considered in my test.

I've put a quick clip comparing the 1DIV and 1DX hunt speeds using the 600II and 2x. The difference is really quite amazing, and makes you wonder what's going on under the hood.

http://www.youtube.com/watch?v=QpWLpNCscQo

Jacob,

I purchased a Canon 500 II about 8 months ago. I had serious AF problems with both my 1DIV and 7D bodies. The lens was very slow to focus when I was focused on a nearby subject and then switched to a distant subject. This problem occurred a little bit with no TC and got progressively worse as I added the 1.4X TC II or the 2X TC III.

I returned the lens to Canon. They returned it with a statement something like "The lens meets all factory specifications but we fine tuned it for optimum performance". The AF performance has been MUCH better since then.

I was happy for the better AF performance but very unhappy that I had to pay the approx. $150 for shipping and insurance when I sent it to Canon. Canon did pay for the return shipping.

Good luck.

Jacob,

One thing I find really hard to believe (not that I'm doubting your results) is that the 600 II and 1DX combo focus at equal speed when using the bare lens or with the 1.4 and especially the 2.0 tc's.  This defies logic...............

Brian, I would have thought so too had I not witnessed it myself with my gear. There is no visible slowdown to note.

Brian E. Small wrote:Jacob,

One thing I find really hard to believe (not that I'm doubting your results) is that the 600 II and 1DX combo focus at equal speed when using the bare lens or with the 1.4 and especially the 2.0 tc's.  This defies logic...............

It is amazingly fast with the 2x. I did an informal comparison this spring comparing my 5Dmark3 and the mark4. The 5D blew away the mark4 with the 2X on. I thought there might be a small difference(I actually thought the mark4 would be better), but it's a drastic difference. Drastic enough that I sold the mark4 and got the Dx..........I find it quite interesting that canon didn't even allow AF at f8 initially, and yet it outperforms the previous bodies at that aperture? Really makes you wonder what is going on at Canon HQ.

Greg's result is not surprising to me at all. I pointed this out last year when I first reviewed the 1DX, the AF does not slow down when adding a 2X TC III to MKII lenses. The CPU in the MKII super telephoto lenses, the MKIII TCs and the 1DX AF module are design-matched to each other and maximum performance is achieved when using them together. It blows the MK4 out of the water in this regard.

ahazeghi wrote:Greg's result is not surprising to me at all. I pointed this out last year when I first reviewed the 1DX, the AF does not slow down when adding a 2X TC III to MKII lenses. The CPU in the  MKII super telephoto lenses, the  MKIII TCs and the 1DX AF module are design-matched to each other and maximum performance is achieved when using them together. It blows the MK4 out of the water in this regard.

The question both I and Jacob have, is why the 600 is so much slower on the Mk4 than other superteles? I can understand an improvement when used with a new gen body, but it's almost as if older bodies are crippled rather just simply focusing a bit slower using the new superteles.

Greg Schneider wrote: The question both I and Jacob have, is why the 600 is so much slower on the Mk4 than other superteles? I can understand an improvement when used with a new gen body, but it's almost as if older bodies are crippled rather just simply focusing a bit slower using the new superteles.

I did not see this with my 600 II and MK4. It felt a bit faster to acquire focus compared to my 500, but I always use the limiter switch (set to far range 16m-inf). I don't have a MK4 anymore to test. Maybe you can email CPS and ask if this is normal, it is an unexpected result.


I know of one person who mentioned their 600 II AF was slower when compared to 800, he sent it to Canon for repair.

As far as I know, Canon can pick any AF hunt speed they want, as long as the body has enough power to drive the AF at that speed. There's no inherent reason that adding TCs has to slow down the speed at which the body drives the AF. I think the only reason Canon has historically slowed down the AF speed when TCs are used is to make the focusing more accurate. For whatever reason, they decided that they didn't need to slow down the AF speed with the 600/1DX even with a 2x, in contrast to what they've done with all the earlier lenses/bodies. So it feels amazingly fast, but it is also more likely to miss focus altogether. I am perfectly happy with that tradeoff with the 1DX, and wish that they had made a similar tradeoff with the 1D4 - whatever setting is determining the AF speed is just way too conservative.

With all due respect to Arash's fine review, I don't think he would have caught this problem in his testing, since it is specific to AF hunting. I've seen two sets of quantitative measurements now demonstrating poor AF performance of older camera bodies on the new 600 (mine and Greg's), and I've heard from a few folks who haven't noticed a problem, but I haven't yet seen a quantitative comparison from anyone showing AF performance with a pre-1DX/5D3 body on a series II supertele that matches the performance on a series I supertele. Would love to see such a comparison, if it exists.

Bruce Sherman wrote:Jacob,

I purchased a Canon 500 II about 8 months ago. I had serious AF problems with both my 1DIV and 7D bodies. The lens was very slow to focus when I was focused on a nearby subject and then switched to a distant subject. This problem occurred a little bit with no TC and got progressively worse as I added the 1.4X TC II or the 2X TC III.

I returned the lens to Canon. They returned it with a statement something like "The lens meets all factory specifications but we fine tuned it for optimum performance". The AF performance has been MUCH better since then.

I was happy for the better AF performance but very unhappy that I had to pay the approx. $150 for shipping and insurance when I sent it to Canon. Canon did pay for the return shipping.

Good luck.

Good to know that Canon can perhaps fix the problem.  I wonder how the "fixed" series II lens would compare to a series I lens in AF hunt speed.

I sent my 600 II to Canon for the exact same problem. They had a look and I believe that they replaced the AF module, but after the "fix" I didn't notice much improvement in the AF performance.
With the 1D4, it still takes a long time when it hunts for focus.